Process of making carbazole indophenols



m mes Patented Aug. 16, 1932 s Get RAYMQNDWQ HESS, :somnuFFALm:NEWEIQRKQ AND ORIN :1). CUNNINGHAM, '01? INDIAN APOLIS; :IE-IEDIANA; essmmss mo im'rmNAL ANILI'N or NEWXOEKyN. iY-g cor ronerion F -NEW:oRK"

tIiRqq1 ss-bi; MAKF-ING .CABBAZOLE INDOIEI-IENOLS This il ventig i relates tQ: i riprovementjs; in the manufacture of "llldOPhbIlOlS, ,andzmore; t

I particularly te indephenols producedbythe cehde nsation of a pstra itresophenol with This application. is: a continuagtion in part fi rlefipf reih et e g eral y mp cyed. for the ma i facture of: indefphenels by the condensation, of p-nitresophegnol with car; bzizole has been to add, with stirring and cool .in g either theselid p-nitposophenol, or a sulur acid; lut o' c 1 p-n r f 'ophen lg o a sulfuric acid solr tigl of; carbazole and sub quen ly.pem'ingsth re ti -mas j n ce. t ri g hep' c ipifiat d indophen d W sh ng itw th terv i'ntil itshd a neu reaction.

The pr sent nve t s asedw pcn h s m fieryv .a ii dQphenqlsg ceu a ured y. the condensation of "carbazole' and pnitiQSo :Pll,?.1.1,0l-.ill thcip c renqe. of. a su b c n ensn'gi gent, snc asrs llfuriciacid,vare.produc d. h. uperior y eldsifc a p rer, in lqphenol and with lessbyeprpductprovided th-e cOjnd-L me f, th c nd ns tion .are such h fer.

phenol-j; h t i zdnringthe,condensatiqnlet J ibazolegand ,n trpsep encl toproducceindos p eeoll e;

' er bfiiqneanl exc ss, o ,iiitmsophensl ove d fibe s at :nece w y t li i :wmhi e i cohdense with the ca rb azple sincewev halve, fom1d .,th t.c rhazele reac sw h indophenol o l pmd e bylq md e e mi t at 'p-n tfo cr L ph n l] e We a a-Y a s z-i i 1: ,o:z, r that' erstr ngth'; 0L the isulfupic a'cid, empleyed and the ,tem pergi ure at which-the rcondehsatieh of the p-hi IQSQphe l with the carbez91,e is car ried eut are eztch of impqrtapce in securing I the production of an indophenol of superior q ality. nd. i mproved" y d -V, We ve found ,should; he 1 present s thlfmlgholih:

. L. ha "t wer. hQfimPQmt-ure h sk tbscqsdsnsst se can r srsnflriscarr d A ipfi arbith ie p tobeml, 1926.; .Seria1 Ne."143 ,295,

by carrying out 'thezcondensation" at a temperature nethigher than abeutv 5 Cz arid :preferablyhot above about 0C., and stillfi I more preferably netaboveabotut f 5 (1;, and

may adva'ntzr g e ously. be carried} out down to a temperatureaslow as 30C., or. lower.

I We have-also fOLlilCithlt imprevedlresults fare obtained by the use Of sulfuric ztcidfof" suchstrength that at the completion Of the cendensation the streng REL-CHEMICAL GOTdPAN-Y; IIJG,

th of the spentfacid: i

will be abo'iit 93"t6 94 per cent; An acid Of this strengthihas the lewest viscosity andfth e lowest freezing poiht of sulfuric acid's'iwhich" liebetween and percent strength. The

initial use of a, sulfuric acid whichlin 0r du'ring the condensation givesfe vspentxacid (if-i about 93' to 94' percent permits carrying eut the precess at low temperatures down to; a polnt approximately thatbf. the freezing p point ofthe initial acid or of the spent acidr freezes at approximately +5 C. andUlO'O formed therefrom: 85, percent sulfuric'acid i 945 percent .sulfiiric' acid freezes rat abfoutif than indicated can be'usedinthe condensation, the use of such ah acid makes it necesa wvhich gives a Weakeror strortgerspentacid ea h-1 1. 50 nb zqle p e ent in: t cb n-L ai ies. med m. th re. is n w yssa eth am m rprs ntmqr he? qne cl O nit so sary because of its higher freezihgpoint; to carry: put the condensat en at hlgher temper etliresl than otherwise, KIIClthQ disadvantages which restilt' therefrom depend up qh the amountsof variatio n' of the final strengthef ithespent acid from about 93 to .94 percent."

A sulfuric acid having an iriitiallstrength'ofz 1 about 98.5 to 96 yperce'nt can be" advantm geously used and .the'tetal Qmountbfsicidm;

plyed is preferably such that a speiit acid eff? about 93 to 94 percent strength is present at? the the'c nd-en tin An K of this strength permits the reecti'dn mixture to be] vigorously and thoroughly, agitatede'nd H permits carrying the reactien'out te'cein- P16151011. at .a temperature from 5 C. to

initial strengthbf about 95 to 96. percent-are sulfuricacid of the strength-and atthe temabout 5 to 6 times the weight of carbazole employed in the condensation. This amount of acid is considerably less than that employed in heretofore proposed processes for effecting this condensation, and in consequence has economic advantages. V

For best results, therefore, we make use of peratures indicated together with the use of such an amount of nitrosophenol that there will always be an excess of out the reaction. I.

We have further discovered that pouring the reaction mass into dilute caustic alkali solution containing ice so as'to maintain a temperature around 0 C. during the precipita'tion of the indophenol produces more uniform, results with'reference to yields and it present througln quality of product than does the usual manner'of precipitating the indophenol by pouring the reaction mass onto ice.

According to the present invention, we add a sulfuric acid solution of carbazole to a sulfuric acid solution of p-nitrosophenolor a homologue or derivative thereof, or we add dry'carbazole to a sulfuric acid solution of p-nitr osophenol or a homologue or derivative thereof, or we add an intimate mixture of carbazol-e'and excess of p-nitrosophenol or a.

homologue or a derivative thereof to sulfuric acid; and in each case we always have present in the condensing medium an excess of p-nitrosophenol (or a homologueor derivative thereof) both during and at the completion of the combination, and the reaction is preferably carried out at a. temperature not higher than about +5 0., or better, not higher than about 0 0., or still better, not

above about 5 C. But the condensation may be carried out atjany desired tempera-' ture between about 5 C. and a temperature just above the freezing point of the acid or the acid solution.

The invention will befurther illustrated by'the following specific examples, but it will be understood that the invention is not limited thereto. The parts are by weight.

Example J.e1 30 parts of p-nitrosophenol are dissolved in 3000 parts of sulfuric acid of 94 percent strength,-which are well stirred and well cooled by external means, To this solution, whilst stirringahd cooling well,

there is added in small portions at a time 167- parts of dry, pulverized carbazole, at such a rate that the temperature ofthesolution does not exceed about +5 Cl, preferably maintaining the temperatures between 0 C. and 30 C., care being taken to avoid local overheating. The reaction is complete within a relatively short time, and when complete the reaction mixture is poured cautiously intoa well stirred solution composed of aboutfQetOO parts of caustic soda, 20,000partsof water, and sufficient ice to maintain the temperature during neutralization at approximately 0 C.

Suificient caustic s da-Shana beu'sed so that the solution is V-slightI-yalkaline after all the acid is n'eutralized. The precipitated indophenol is filtered off at once and washed with water until free from alkali and sulfates. It may be dried at about 60 C.

Example 2. parts of p-nitrosophenol are'di'ssolved in 500 parts of well stirredandv well cooled sulfuric ,acid of 95 percent strength,- and into this solution, whilst stirring and cooling well the same, there is introduced a well cooled solution of 167 parts of carbazole dissolved in 500 parts of 95 percent sulfuric acid, the mixed solution being maintained at atemperature not to exceed 55 Q.,preferablybetween 5 C. and 15 C. during the condensation. The reaction is. almost instantaneous and is, completewithin a relatively short time, and when completed. the indophenol is precipitated and isolated in any suitable mannerfor in a manner simi lar. tothat described in Example- 1,., It willv be. noted thatthe total amount of sulfuric:

rate that the. temperature does not exceed -5 C. When the condensation is complete, the indophenol" is precipitated and isolated in a manner similar to that'described ini Example 1-. V

Example 4.'-130;,parts ofp-nitrosophenol are dissolved'in1500-parts of sulfuric acid of 94 percent strength, lt b8lI1g,;Wll stirred and well cooled to about -3J CI. to 35*?, CI.

Into this solution, while agitating and. cool ing well, there is introduced a well cooled solution of 167 partscarbaz'ole dissolved. in

1500 parts sulfuric acid of 94 percent strength at such a rate that the temperatureof the mixture doesnot exceed about 30 C.

throughout the condensation. When the condensation is complete, the indophenol is ,pre-

cipitated and isolatedas described in any of the examples given above.

' A large excess of p-nitrosophenol, even to I the extent of 50 percent or more, hasno harmful effect, while an excess of carbazole is very detrimental. The amount of sulfuric acidmay vary but the amount should be at least sufficientto yield a solution or suspensioncapable of'being vigorously and efliciently stirred in order to avoid local overheating. 7

It will thus be seen that the present invention effects-the condensation of carbazole.

with nitrosophenol in the presence of a condensing agentisuch as sulfuric flztlldi fltdflw temperatures and in such a manner; that i at all times during the condensation; an excess of nitrosophenol is present whereby side reactions which produce byproducts, particularly by-products arising-from the 'interace tion of carbazole and indoph-enol, are elimi nst-odor minimized. V r

The invention is applicable tothemanuiacture of indophenols producedby the con- 'densation of carbazole'with p-nitrosophenol or: homologues or derivatives thereof in the presence ofsulfuric acid. V

a In the claims, it will be understood that the term para-nitrosophenol compound denotes and includes p-nitrosophen ol,its homologues derivatives, and the term f low temperature is used to cover the range of tern eratn-refrom about +5 C. to-aboutj -30:

1We claim:

-1. In the -manu facture ofan .indophenolic compound by condensing carbazole with a para-nitrosophenol compound in thepresence of sulfuric acid, the improvement which comprises maintaining throughout the condensation a-n excess of the para-nitrosophenol-compound.

2. In the manufacture of 7 an indoph enolic compound by condensing .carbazole with I a para-nitrosephenol compound, the improvementwhich comprises introducing a sulfuric acid solution of carbazole into a sulfuric. acid solution ofa para-nitrosophenol compound, :andthroughout the condensation maintaining a temperature below +5 C. and an ex cess of the para-nitrosophenol compound.

'3. In the manufacture of an indophen-ol by condensing carbazole with para-nitrosopl1enol'i'n the presence of sulfuriczacid. the improvement which, comprises maintaining; an excess of paraenitrosophenol throughout the condensation. 7

4. the manufactureof an indophenol by condensing 'carbazole with para-nitrosophenol, theimprovement which comprises introducing a sulfuric-acid solutionof carbazole into-a sulfuricacid solution of para-nitrosophenol, and throughout the -,condensation maintaining a temperaturebelow 5 C. and -anexcess of para-nitrosophenol.

3-5. In the manufacture of a condensation product by condensing carbazole with ,a

para-nitrosophenol compound, the process which comprises bringing one moleculanproportion of carbazole into contact with more than one molecularproportion of the paralnitrosophenol compound in thespresence of sulfuric acidat a temperaturemaintained below about+5 0., and at the completion of the condensation pouring the reaction-mass into a dilute solution of causticsoda main- ...tained at a temperature not above-about C. 6. In the manufacture of a condensation product: by condensing carbaaole with para- .nitrosophenol theprocess which comprises in the the amount and-strength 'ot rsulfuric aci tained at atemperature' of about 0 C i-and recoveringv the-precipitate.

bringing one molecular proportion iof carbazole into contact With more than-one I molecular proportion of :para-nitrosophenol inthe presence of sulfuric acid at atempe'rar 'ture maintained below about C. and

pouring the reaction mass intoa dilutesolu tion oiic'austicsoda maintained. at astemperav ture ofaboutO C. V 1 i '7. 'Inft-he manufactureof in dophenolic compouni'the-process which compr1sesconper cent, maintaining inthe reaction mixture throughout thecondensation an excess of the para-nitrosophenol compound, subsequently precipitating the indophenol compoundby the addition o-f the reaction mixture :towian excess of anaqueousfsolution :of caustic -alkali maintained at a temperature (if-about 0 0., and recovering the precipitate.

8. In theimanufac-ture of an indophcnolic compound, the :process which comprises condensing carbazole with para-nitrosophenol presence of. sulfnric' ac'idmaintained at a temperatureof about +.5- C. to C.

being suchthat at'the completion of thereondensation its strength is approxiniatlyaQS to- 94 percent, -maintainingkin the reaction mixture throughout. the condensation 11111 excess of para-nitrosoplienol, subsequently precipitating the indophenol 7 compound by the addition'of; the reaction mixture tozanexcess of an aqueous solution of causticsodamain- 9. In' the production of an indophenolic compound shy the condensation of 'carb-azole with a para-nitrosophenol compound in the presence of sulfuricacid, the'improvement :a temperature maintained between about: 5

tion-iof carbazole present. 7

10. In the production :of-aniindopheno l'ic compound bythe condensation of carbazole with para-nitrosop-henol in the presence of H sulfuric acid, the improvementwhich 'eomprises having present at all times during t he 'condensatiton more th-anon'e molecular proportion of para-nitrosophenol fcr each m'olecular proportion of carbazole present.

11. In the production ofan indophenoli'c C; and 30?*C., andhaving'xpresent Iatrall times during the condensation more than one -molecular proportion of the 'parar-nit'rosophenol compound for each'molecular proporcompound by the condensation ofcarbazole with a para-nitrosophenol compound in the presence of sulfuric acidfthe improvement which comprises carrying out thecondensawhich comprises carrying-soutwthe reactionat "i I tion to completion at a temperature not above about O. J 4 1 f 12. In the production 1 of an indophenolic compound by the condensation of carbazole with para-nitrosophenol in-the presence of sulfuric acid, the improvement which com,- prises carrying out the condensation at a temperature not above about 09- O. I r

13. In'the production of an indophenolic compoundby the condensation of carbazole with a'para-nitrosophenol compound, the improvement which comprises carrying out the condensation-in the presence of sulfuric acid of such an amount and strength that at the completion of thecondensation the strength of the acid: is approximately 93-to 94 percent. J a Y 14. III-the production of anindoplienolic compound by the condensation. of carbazole with paranitrosopheriol, the improvement which comprises carryingout the condensationin the presence-of sulfuric acid of such strength and amount that at the completion of the condensation the strength of the acid is approximately 93'to 94: percent.

"15." In the production of an indophenolic compound by condensing carbazole with, a

para-nitrosophenol compound in the presence of sulfuric acid," and subsequently isolating the indophenolic compound, a process which comprises adding the reaction mixture at the completion of the condensation to a suflicient amount of caustic alkali-in solution to neutralize the sulfuric acid and to precipitate the indophenolic compound.

. 16. In-theproduction of an indophenolic compound by condensing carbazole with para-nitrosophenol in the presence of suluric and subsequently isolating. the indophenolic compound, a process which comprises addlng the reactlon mixture at the completion of the condensation to a sufficient amount of caustic soda in solution to neutra- :lize the sulfuric acid and to precipitate the 'indophenolic compound.

17. The manufacture .of condensation products of; carbazole and .p-nitroso-substr tuted-phenols by bringing carbazole. and a p- 'nitrososubstituted phenol together in pres ence of a; condensing agent at a temperature not exceeding about -5C.' and maintaining the reaction-mixture throughout the condensation at a temperature below 0C.

- 18. The manufacture of condensation products of carbazole andp-nitroso-substituted phenolsby bringing carbazole and a p-nitroso-substituted phenol together in pres- .ence of sulfuric acid at a temperature not exceeding about +5 0. and maintaining the reaction-mixture throughout the condensation v at a temperatureobelow 0C."

19. The manufacture. of condensation products of carbazole and p-nitroso substituted phenols by bringing carbazole and apnitroso-substituted'phenol together in pres- 21. The T manufacture at once. 1

at which the reacting-substances are initially brought into contact; I y a 20.'The- -manufacture of" condensation products of carbazole and -p-nitroso-substituted'phenols by bringing carba zole and a p-' nitros'o-substituted I phenol together in presence of sulfuric acid'at a temperature not exceeding about 5C; and maintainingithe reaction-mixture throughout thQCOIlClBIlSZL- tion at substantially the same temperature at which the reacting substances are initially brought togetherk of condensation products of carbazole and p-nitroso-substituted phenols by bringing together carbazole and a p-nitroso-substituted phenolin presence of sulfuric acid at a temperature not exceeding about 5 (1, maintaining there'- action-mixture throughout the condensation at a temperature below 0 (1, and'precipitating the condensation product by addition of the reaction-mixture to dilute aqueous alkali in excess.

'22. The manufacture of a condensation product of carbazole and a p-nitrosophenol gether in presence of substantially 93.5 to 96 j per-cent sulfuric acid at a temperature not exceeding about 5 C. and maintaining the reaction-mixture throughout the condensation at' a temperature below 0 C. v

24. Them'anufac'ture of a condensation product of carbazole and p-nitrosophenol by bringing carb azole and p-nitrosophenol 'together in presence ofsulfuric acid: at a tem perature not exceeding 'a.bout '5 Cfand ma ntaining the react10n-m1xture throughout the' condensation at substantially the same temperature at which the reacting substances are initially brought into contact.

" In the manufacture of in dophenolic compounds by condensing carbazole with a para-nitrosophenol compound and subsequently adding the reaction-mixture to a caustic soda solution whereby the indophenolic compound is precipitated, the step which comprises filtering off the precipitate [26. In the manufacture of an indophenolic compound, the process'which comprises condensing carbazole with a para-nitrosophenol compoundin the presence of sul- In the manufacture of a condensation furic acid having an initial strength of about 93.5 to- 96 percent, the amount of sulfuric acid being such that atthe completion of the condensation the strength of the acid is about 93-94 percent.

27. In the manufacture. of an indophenol by the condensation of carbazole with p-nitrosophenol in the presence of sulfuric acid, the improvement which comprises bringing carbazole and p-nitrosophenol into reaction with one another in the presence of sulfuric acid havingan initial strength of about to 96 percent, the total amount by weight of the sulfuric acid employed being about five to six times the weight of the carbazole used in the condensation with the p-nitrosophenol.

28. In the manufacture of an indophenolic compound, the process which comprises condensing carbazole with a nitrosophenol in the presence of sulfuric acid at a temperature maintained between about +5 C. and about 30 C.

In testimony whereof we affix our signatures.

RAYMOND W. HESS. ORIN D. CUNNINGHAM. 

